// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_COMPOSITOR_LAYER_H_
#define UI_COMPOSITOR_LAYER_H_

#include <stddef.h>

#include <string>
#include <vector>

#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/message_loop/message_loop.h"
#include "cc/base/region.h"
#include "cc/layers/content_layer_client.h"
#include "cc/layers/layer_client.h"
#include "cc/layers/surface_layer.h"
#include "cc/layers/texture_layer_client.h"
#include "cc/resources/texture_mailbox.h"
#include "cc/surfaces/surface_id.h"
#include "third_party/skia/include/core/SkColor.h"
#include "third_party/skia/include/core/SkRegion.h"
#include "ui/compositor/compositor.h"
#include "ui/compositor/layer_animation_delegate.h"
#include "ui/compositor/layer_delegate.h"
#include "ui/compositor/layer_threaded_animation_delegate.h"
#include "ui/compositor/layer_type.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/image/image_skia.h"
#include "ui/gfx/transform.h"

class SkCanvas;

namespace cc {
class ContentLayer;
class CopyOutputRequest;
class Layer;
class NinePatchLayer;
class ResourceUpdateQueue;
class SolidColorLayer;
class SurfaceLayer;
class TextureLayer;
struct ReturnedResource;
typedef std::vector<ReturnedResource> ReturnedResourceArray;
}

namespace ui {

class Compositor;
class LayerAnimator;
class LayerOwner;

// Layer manages a texture, transform and a set of child Layers. Any View that
// has enabled layers ends up creating a Layer to manage the texture.
// A Layer can also be created without a texture, in which case it renders
// nothing and is simply used as a node in a hierarchy of layers.
// Coordinate system used in layers is DIP (Density Independent Pixel)
// coordinates unless explicitly mentioned as pixel coordinates.
//
// NOTE: Unlike Views, each Layer does *not* own its child Layers. If you
// delete a Layer and it has children, the parent of each child Layer is set to
// NULL, but the children are not deleted.
class COMPOSITOR_EXPORT Layer
    : public LayerAnimationDelegate,
      public LayerThreadedAnimationDelegate,
      NON_EXPORTED_BASE(public cc::ContentLayerClient),
      NON_EXPORTED_BASE(public cc::TextureLayerClient),
      NON_EXPORTED_BASE(public cc::LayerClient) {
public:
    Layer();
    explicit Layer(LayerType type);
    ~Layer() override;

    static const cc::LayerSettings& UILayerSettings();
    static void InitializeUILayerSettings();

    // Retrieves the Layer's compositor. The Layer will walk up its parent chain
    // to locate it. Returns NULL if the Layer is not attached to a compositor.
    Compositor* GetCompositor()
    {
        return const_cast<Compositor*>(
            const_cast<const Layer*>(this)->GetCompositor());
    }
    const Compositor* GetCompositor() const;

    // Called by the compositor when the Layer is set as its root Layer. This can
    // only ever be called on the root layer.
    void SetCompositor(Compositor* compositor,
        scoped_refptr<cc::Layer> root_layer);
    void ResetCompositor();

    LayerDelegate* delegate() { return delegate_; }
    void set_delegate(LayerDelegate* delegate) { delegate_ = delegate; }

    LayerOwner* owner() { return owner_; }

    // Adds a new Layer to this Layer.
    void Add(Layer* child);

    // Removes a Layer from this Layer.
    void Remove(Layer* child);

    // Stacks |child| above all other children.
    void StackAtTop(Layer* child);

    // Stacks |child| directly above |other|.  Both must be children of this
    // layer.  Note that if |child| is initially stacked even higher, calling this
    // method will result in |child| being lowered in the stacking order.
    void StackAbove(Layer* child, Layer* other);

    // Stacks |child| below all other children.
    void StackAtBottom(Layer* child);

    // Stacks |child| directly below |other|.  Both must be children of this
    // layer.
    void StackBelow(Layer* child, Layer* other);

    // Returns the child Layers.
    const std::vector<Layer*>& children() const { return children_; }

    // The parent.
    const Layer* parent() const { return parent_; }
    Layer* parent() { return parent_; }

    LayerType type() const { return type_; }

    // Returns true if this Layer contains |other| somewhere in its children.
    bool Contains(const Layer* other) const;

    // The layer's animator is responsible for causing automatic animations when
    // properties are set. It also manages a queue of pending animations and
    // handles blending of animations. The layer takes ownership of the animator.
    void SetAnimator(LayerAnimator* animator);

    // Returns the layer's animator. Creates a default animator of one has not
    // been set. Will not return NULL.
    LayerAnimator* GetAnimator();

    // The transform, relative to the parent.
    void SetTransform(const gfx::Transform& transform);
    gfx::Transform transform() const;

    gfx::PointF position() const { return cc_layer_->position(); }

    // Return the target transform if animator is running, or the current
    // transform otherwise.
    gfx::Transform GetTargetTransform() const;

    // The bounds, relative to the parent.
    void SetBounds(const gfx::Rect& bounds);
    const gfx::Rect& bounds() const { return bounds_; }
    const gfx::Size& size() const { return bounds_.size(); }

    // The offset from our parent (stored in bounds.origin()) is an integer but we
    // may need to be at a fractional pixel offset to align properly on screen.
    void SetSubpixelPositionOffset(const gfx::Vector2dF& offset);
    const gfx::Vector2dF& subpixel_position_offset() const
    {
        return subpixel_position_offset_;
    }

    // Return the target bounds if animator is running, or the current bounds
    // otherwise.
    gfx::Rect GetTargetBounds() const;

    // Sets/gets whether or not drawing of child layers should be clipped to the
    // bounds of this layer.
    void SetMasksToBounds(bool masks_to_bounds);
    bool GetMasksToBounds() const;

    // The opacity of the layer. The opacity is applied to each pixel of the
    // texture (resulting alpha = opacity * alpha).
    float opacity() const;
    void SetOpacity(float opacity);

    // Returns the actual opacity, which the opacity of this layer multipled by
    // the combined opacity of the parent.
    float GetCombinedOpacity() const;

    // Blur pixels by this amount in anything below the layer and visible through
    // the layer.
    int background_blur() const { return background_blur_radius_; }
    void SetBackgroundBlur(int blur_radius);

    // Saturate all pixels of this layer by this amount.
    // This effect will get "combined" with the inverted,
    // brightness and grayscale setting.
    float layer_saturation() const { return layer_saturation_; }
    void SetLayerSaturation(float saturation);

    // Change the brightness of all pixels from this layer by this amount.
    // This effect will get "combined" with the inverted, saturate
    // and grayscale setting.
    float layer_brightness() const { return layer_brightness_; }
    void SetLayerBrightness(float brightness);

    // Return the target brightness if animator is running, or the current
    // brightness otherwise.
    float GetTargetBrightness() const;

    // Change the grayscale of all pixels from this layer by this amount.
    // This effect will get "combined" with the inverted, saturate
    // and brightness setting.
    float layer_grayscale() const { return layer_grayscale_; }
    void SetLayerGrayscale(float grayscale);

    // Return the target grayscale if animator is running, or the current
    // grayscale otherwise.
    float GetTargetGrayscale() const;

    // Zoom the background by a factor of |zoom|. The effect is blended along the
    // edge across |inset| pixels.
    void SetBackgroundZoom(float zoom, int inset);

    // Set the shape of this layer.
    SkRegion* alpha_shape() const { return alpha_shape_.get(); }
    void SetAlphaShape(scoped_ptr<SkRegion> region);

    // Invert the layer.
    bool layer_inverted() const { return layer_inverted_; }
    void SetLayerInverted(bool inverted);

    // Return the target opacity if animator is running, or the current opacity
    // otherwise.
    float GetTargetOpacity() const;

    // Set a layer mask for a layer.
    // Note the provided layer mask can neither have a layer mask itself nor can
    // it have any children. The ownership of |layer_mask| will not be
    // transferred with this call.
    // Furthermore: A mask layer can only be set to one layer.
    void SetMaskLayer(Layer* layer_mask);
    Layer* layer_mask_layer() { return layer_mask_; }

    // Sets the visibility of the Layer. A Layer may be visible but not
    // drawn. This happens if any ancestor of a Layer is not visible.
    void SetVisible(bool visible);
    bool visible() const { return visible_; }

    // Returns the target visibility if the animator is running. Otherwise, it
    // returns the current visibility.
    bool GetTargetVisibility() const;

    // Returns true if this Layer is drawn. A Layer is drawn only if all ancestors
    // are visible.
    bool IsDrawn() const;

    // Returns true if this layer can have a texture (has_texture_ is true)
    // and is not completely obscured by a child.
    bool ShouldDraw() const;

    // Converts a point from the coordinates of |source| to the coordinates of
    // |target|. Necessarily, |source| and |target| must inhabit the same Layer
    // tree.
    static void ConvertPointToLayer(const Layer* source,
        const Layer* target,
        gfx::Point* point);

    // Converts a transform to be relative to the given |ancestor|. Returns
    // whether success (that is, whether the given ancestor was really an
    // ancestor of this layer).
    bool GetTargetTransformRelativeTo(const Layer* ancestor,
        gfx::Transform* transform) const;

    // See description in View for details
    void SetFillsBoundsOpaquely(bool fills_bounds_opaquely);
    bool fills_bounds_opaquely() const { return fills_bounds_opaquely_; }

    // Set to true if this layer always paints completely within its bounds. If so
    // we can omit an unnecessary clear, even if the layer is transparent.
    void SetFillsBoundsCompletely(bool fills_bounds_completely);

    const std::string& name() const { return name_; }
    void set_name(const std::string& name) { name_ = name; }

    // Set new TextureMailbox for this layer. Note that |mailbox| may hold a
    // shared memory resource or an actual mailbox for a texture.
    void SetTextureMailbox(const cc::TextureMailbox& mailbox,
        scoped_ptr<cc::SingleReleaseCallback> release_callback,
        gfx::Size texture_size_in_dip);
    void SetTextureSize(gfx::Size texture_size_in_dip);
    void SetTextureFlipped(bool flipped);
    bool TextureFlipped() const;

    // Begins showing content from a surface with a particular id.
    void SetShowSurface(cc::SurfaceId surface_id,
        const cc::SurfaceLayer::SatisfyCallback& satisfy_callback,
        const cc::SurfaceLayer::RequireCallback& require_callback,
        gfx::Size surface_size,
        float scale,
        gfx::Size frame_size_in_dip);

    bool has_external_content()
    {
        return texture_layer_.get() || surface_layer_.get();
    }

    // Show a solid color instead of delegated or surface contents.
    void SetShowSolidColorContent();

    // Sets the layer's fill color.  May only be called for LAYER_SOLID_COLOR.
    void SetColor(SkColor color);
    SkColor GetTargetColor();
    SkColor background_color() const;

    // Updates the nine patch layer's image, aperture and border. May only be
    // called for LAYER_NINE_PATCH.
    void UpdateNinePatchLayerImage(const gfx::ImageSkia& image);
    void UpdateNinePatchLayerAperture(const gfx::Rect& aperture_in_dip);
    void UpdateNinePatchLayerBorder(const gfx::Rect& border);

    // Adds |invalid_rect| to the Layer's pending invalid rect and calls
    // ScheduleDraw(). Returns false if the paint request is ignored.
    bool SchedulePaint(const gfx::Rect& invalid_rect);

    // Schedules a redraw of the layer tree at the compositor.
    // Note that this _does not_ invalidate any region of this layer; use
    // SchedulePaint() for that.
    void ScheduleDraw();

    // Uses damaged rectangles recorded in |damaged_region_| to invalidate the
    // |cc_layer_|.
    void SendDamagedRects();
    void ClearDamagedRects();

    const cc::Region& damaged_region() const { return damaged_region_; }

    void CompleteAllAnimations();

    // Suppresses painting the content by disconnecting |delegate_|.
    void SuppressPaint();

    // Notifies the layer that the device scale factor has changed.
    void OnDeviceScaleFactorChanged(float device_scale_factor);

    // Notifies the layer that one of its children has received a new
    // delegated frame.
    void OnDelegatedFrameDamage(const gfx::Rect& damage_rect_in_dip);

    // Requets a copy of the layer's output as a texture or bitmap.
    void RequestCopyOfOutput(scoped_ptr<cc::CopyOutputRequest> request);

    // ContentLayerClient
    gfx::Rect PaintableRegion() override;
    scoped_refptr<cc::DisplayItemList> PaintContentsToDisplayList(
        ContentLayerClient::PaintingControlSetting painting_control) override;
    bool FillsBoundsCompletely() const override;
    size_t GetApproximateUnsharedMemoryUsage() const override;

    cc::Layer* cc_layer_for_testing() { return cc_layer_; }

    // TextureLayerClient
    bool PrepareTextureMailbox(
        cc::TextureMailbox* mailbox,
        scoped_ptr<cc::SingleReleaseCallback>* release_callback,
        bool use_shared_memory) override;

    float device_scale_factor() const { return device_scale_factor_; }

    // Forces a render surface to be used on this layer. This has no positive
    // impact, and is only used for benchmarking/testing purpose.
    void SetForceRenderSurface(bool force);
    bool force_render_surface() const { return force_render_surface_; }

    // LayerClient
    scoped_refptr<base::trace_event::ConvertableToTraceFormat> TakeDebugInfo(
        cc::Layer* layer) override;

    // Whether this layer has animations waiting to get sent to its cc::Layer.
    bool HasPendingThreadedAnimationsForTesting() const;

    // Triggers a call to SwitchToLayer.
    void SwitchCCLayerForTest();

private:
    friend class LayerOwner;

    void CollectAnimators(std::vector<scoped_refptr<LayerAnimator>>* animators);

    // Stacks |child| above or below |other|.  Helper method for StackAbove() and
    // StackBelow().
    void StackRelativeTo(Layer* child, Layer* other, bool above);

    bool ConvertPointForAncestor(const Layer* ancestor, gfx::Point* point) const;
    bool ConvertPointFromAncestor(const Layer* ancestor, gfx::Point* point) const;

    // Implementation of LayerAnimatorDelegate
    void SetBoundsFromAnimation(const gfx::Rect& bounds) override;
    void SetTransformFromAnimation(const gfx::Transform& transform) override;
    void SetOpacityFromAnimation(float opacity) override;
    void SetVisibilityFromAnimation(bool visibility) override;
    void SetBrightnessFromAnimation(float brightness) override;
    void SetGrayscaleFromAnimation(float grayscale) override;
    void SetColorFromAnimation(SkColor color) override;
    void ScheduleDrawForAnimation() override;
    const gfx::Rect& GetBoundsForAnimation() const override;
    gfx::Transform GetTransformForAnimation() const override;
    float GetOpacityForAnimation() const override;
    bool GetVisibilityForAnimation() const override;
    float GetBrightnessForAnimation() const override;
    float GetGrayscaleForAnimation() const override;
    SkColor GetColorForAnimation() const override;
    float GetDeviceScaleFactor() const override;
    cc::Layer* GetCcLayer() const override;
    LayerThreadedAnimationDelegate* GetThreadedAnimationDelegate() override;
    LayerAnimatorCollection* GetLayerAnimatorCollection() override;

    // Implementation of LayerThreadedAnimationDelegate.
    void AddThreadedAnimation(scoped_ptr<cc::Animation> animation) override;
    void RemoveThreadedAnimation(int animation_id) override;

    // Creates a corresponding composited layer for |type_|.
    void CreateCcLayer();

    // Recomputes and sets to |cc_layer_|.
    void RecomputeDrawsContentAndUVRect();
    void RecomputePosition();

    // Set all filters which got applied to the layer.
    void SetLayerFilters();

    // Set all filters which got applied to the layer background.
    void SetLayerBackgroundFilters();

    // Cleanup |cc_layer_| and replaces it with |new_layer|.
    void SwitchToLayer(scoped_refptr<cc::Layer> new_layer);

    // We cannot send animations to our cc_layer_ until we have been added to a
    // layer tree. Instead, we hold on to these animations in
    // pending_threaded_animations_, and expect SendPendingThreadedAnimations to
    // be called once we have been added to a tree.
    void SendPendingThreadedAnimations();

    void SetCompositorForAnimatorsInTree(Compositor* compositor);
    void ResetCompositorForAnimatorsInTree(Compositor* compositor);

    const LayerType type_;

    Compositor* compositor_;

    Layer* parent_;

    // This layer's children, in bottom-to-top stacking order.
    std::vector<Layer*> children_;

    gfx::Rect bounds_;
    gfx::Vector2dF subpixel_position_offset_;

    // Visibility of this layer. See SetVisible/IsDrawn for more details.
    bool visible_;

    bool force_render_surface_;

    bool fills_bounds_opaquely_;
    bool fills_bounds_completely_;

    // Union of damaged rects, in layer space, to be used when compositor is ready
    // to paint the content.
    cc::Region damaged_region_;

    int background_blur_radius_;

    // Several variables which will change the visible representation of
    // the layer.
    float layer_saturation_;
    float layer_brightness_;
    float layer_grayscale_;
    bool layer_inverted_;

    // The associated mask layer with this layer.
    Layer* layer_mask_;
    // The back link from the mask layer to it's associated masked layer.
    // We keep this reference for the case that if the mask layer gets deleted
    // while attached to the main layer before the main layer is deleted.
    Layer* layer_mask_back_link_;

    // The zoom factor to scale the layer by.  Zooming is disabled when this is
    // set to 1.
    float zoom_;

    // Width of the border in pixels, where the scaling is blended.
    int zoom_inset_;

    // Shape of the window.
    scoped_ptr<SkRegion> alpha_shape_;

    std::string name_;

    LayerDelegate* delegate_;

    LayerOwner* owner_;

    scoped_refptr<LayerAnimator> animator_;

    // Animations that are passed to AddThreadedAnimation before this layer is
    // added to a tree.
    std::vector<scoped_ptr<cc::Animation>> pending_threaded_animations_;

    // Ownership of the layer is held through one of the strongly typed layer
    // pointers, depending on which sort of layer this is.
    scoped_refptr<cc::Layer> content_layer_;
    scoped_refptr<cc::NinePatchLayer> nine_patch_layer_;
    scoped_refptr<cc::TextureLayer> texture_layer_;
    scoped_refptr<cc::SolidColorLayer> solid_color_layer_;
    scoped_refptr<cc::SurfaceLayer> surface_layer_;
    cc::Layer* cc_layer_;

    // A cached copy of |Compositor::device_scale_factor()|.
    float device_scale_factor_;

    // A cached copy of the nine patch layer's image and aperture.
    // These are required for device scale factor change.
    gfx::ImageSkia nine_patch_layer_image_;
    gfx::Rect nine_patch_layer_aperture_;

    // The mailbox used by texture_layer_.
    cc::TextureMailbox mailbox_;

    // The callback to release the mailbox. This is only set after
    // SetTextureMailbox is called, before we give it to the TextureLayer.
    scoped_ptr<cc::SingleReleaseCallback> mailbox_release_callback_;

    // The size of the frame or texture in DIP, set when SetShowDelegatedContent
    // or SetTextureMailbox was called.
    gfx::Size frame_size_in_dip_;

    DISALLOW_COPY_AND_ASSIGN(Layer);
};

} // namespace ui

#endif // UI_COMPOSITOR_LAYER_H_
